In the critique of our MRDDRC application in 2001 the study section stated (p.5): behavioral expertise will need to be added to the Center to provide better input into this area at an early stage of grant development. In response to this suggestion we propose to develop the Neurobehavioral Evaluation Core (NEC) that will provide investigators with this expertise. The primary objective of the NEC is to provide sophisticated neurobehavioral and neuropsychological research support to MRDDRC projects, and to develop or validate new methods for this purpose. Scientific advancement of our understanding of complex neurobehavioral disorders of development is facilitated greatly by our ability to reliably and precisely define the developmental and behavioral phenotype. Measurement of behavioral and cognitive variables is crucial in studies of disease and development that comprise our MRDDRC. Over the past 3-5 years, there has been a substantial increase in the number of MRDDRC projects with a behavioral and/or psychosocial focus. The aims of these studies have been on the developmental, cognitive, and behavioral outcomes in children who have a variety of neurogenetic, neurodevelopmental, or acquired disorders that affect cognition and behaivor. In addition to a rigorous study of the underlying medical condition (e.g. urea cycle disorders or epilepsy), these investigations aim to describe the impact on the child's cognitive and behavioral development. Twenty to thirty years ago, this type of research might have focused on the broad aspects of development, such as the level of intelligence of these children. Newer methods allow a far more in depth focus into such critical developmental factors as attention, executive function, and memory subprocesses. The explosion of developmental neuropsychological knowledge base linking underlying neurological development and disorder with behavioral and cognitive development has further fueled the need for pediatric research to include sophisticated models of neurobehavioral and neuropsychological function. Historically, many studies that could have potentially benefited from examination of neuropsychological and neurobehavioral variables have not included such assessments because of: 1) limited knowledge regarding available measures;2) cost-constraints within research project budgets for expert personnel and/or purchase of testing materials;and 3) lack of access to personnel skilled in the performance of these assessments. The primary goal of the NEC is to improve access to appropriate measures and to enhance the overall quality of neurobehavioral research being conducted throughout the MRDDRC. Within the NEC, we propose to: 1) provide access to an extensive battery of neuropsychological testing services;2) develop and administer neurobehavioral tasks for neuroimaging protocols, including fMRI projects through the Neuroimaging Core;3) provide consultation to MRDDRC investigators on the proper design and use of neurobehavioral and neuropsychological measures in research studies;and 4) train investigators and their staff in the use of these measures. With this increased sophistication investigators will be able to assess several levels of neurobehavioral outcome, e.g., specific neuropsychological processes, such as memory or executive function, together with quality of life functional status. This will be able to be coupled with studies exploring etiologic factors at the genetic level (utilizing the Molecular Genetics, Proteomics and Biochemical Analysis Core) and neuropathophysiologic level (using the Neuroimaging Core).